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. Author manuscript; available in PMC: 2017 Feb 10.
Published in final edited form as: Cell Host Microbe. 2016 Feb 10;19(2):254–266. doi: 10.1016/j.chom.2016.01.002

Figure 2. Histologic lesions in ferret lung 3 days after infection with pandemic H1N1 influenza viruses.

Figure 2

Histopathological assessment of ferret lung infected with 1918 (left column) or CA04 (right column) viruses. A) 1918 virus infection. There is patchy atelectasis and thickening of alveolar walls. “Br” indicates unaffected medium and large bronchioles, and arrows indicate small caliber bronchioles and terminal airways. Stars indicate foci of bronchiolar submucosal gland necrosis and inflammation. B) CA04 infection. “Br” indicates large bronchiole containing a crescent of fibrinocellular exudate. Arrows indicate numerous small caliber bronchioles and terminal airways that have been effaced by necrosis and mixed inflammatory exudates. Adjacent alveolar tissue is consolidated and there is loss of alveolar architectural definition. Stars indicate foci of bronchiolar submucosal gland necrosis and inflammation. C) 1918 infection and D) CA04 infection. Bronchiolar submucosal gland necrosis. Arrows indicate affected glandular acini in which the epithelium is largely absent and lumena are filled with cellular debris, neutrophils, macrophages and eosinophils. Star indicates periglandular infiltrates of lymphocytes, plasma cells, and eosinophils. E) 1918 infection and F) CA04 infection. Small bronchioles and terminal airways, higher magnification of micrographs A and B, respectively. Arrows indicate similarly sized transitional and terminal airways. The airway in E is minimally affected. Dashes in F demark the approximate location of the small airway wall. The indicated airway and adjacent alveoli in F exhibit segmental necrosis and ulceration, and the airway lumen is filled with exudate composed of cellular debris and mixed inflammatory cells (inset F) including numerous eosinophils, fewer macrophages, lymphocytes and neutrophils. G) 1918 infection and H) CA04 infection. Regional atelectasis with effusion (asterisks). Arrows indicate bronchioles, the lumen of the bronchiole in G contains effusion (pink material). H, left inset) a central C-shaped crescent of Type II pneumocyte hyperplasia and adjacent intra-alvoeolar eosinophils, macrophage, and lymphocytes (left and bottom). H, right inset) a cluster of foamy macrophages in an affected alveolus. See also Figure S1.